Israeli troops enter Gaza City in the Gaza Strip in this June 7, 1967 file photo.

Fifty years ago today, one of history’s shortest but most consequential military conflicts began. As the world recalls the Six-Day War, it must understand the distance traveled since and the stubborn persistence of the very forces that fueled the fighting.

Which is to say, though two of Israel’s neighbors now recognize Israel’s right to exist, a rabid refusal by others to accept the presence of a Jewish state in the Mideast remains the chief obstacle to lasting peace.

It was on June 5, 1967, that war erupted: Arab nations hostile to the very idea of the state of Israel, led by Egypt’s Gamal Abdel Nasser, yearned to kill her in the crib. Israel, outnumbered and outgunned and justly fearing destruction, hit hard and fast.

Israeli forces destroyed Egypt’s air force on the ground and followed with sweeping tank thrusts across the sands of Gaza and Sinai to the waters of the Suez Canal. Then, Syria and Jordan attacked — and were likewise quickly subdued, losing the Golan Heights, the West Bank and East Jerusalem, uniting a divided city and opening to all faiths the holy places of the Old City.

War over. Mideast changed forever.

Or has it?

There is peace between Israel and Egypt, inked as part of the 1978 Camp David Accords. There is peace. too, with Jordan. And much of the land of the West Bank is ruled by the Palestinian Authority, where corruption and nepotism, not terrorism, are the biggest threats.

Call all that progress — that could even yield a stable, independent Palestinian state, when leaders and their population get their head around the idea that Israel is part of the neighborhood to stay.

What hasn’t changed: Those whose chief objective is not to live beside Israel but to snuff it out continue to breathe down her neck — and impede the path to peace.

Sinai, returned to Egypt as part of the Camp David treaty, is a lawless place where radical Islamic terrorists kill Egyptian Christian Copts.

Gaza, handed to Yasser Arafat and the Palestinian Authority under the Oslo peace process, has since been seized by Hamas, committed to the elimination of Israel. It is a prison camp, a breeding ground for terrorism and a launch pad for firing rockets into Israel.

Which brings us to Jerusalem. President Trump last week extended for six months a longtime executive waiver on a law that would force him to move the U.S. embassy there. That’s in keeping with U.S. policy and delicate diplomacy.

But don’t confuse diplomacy with fact. Jerusalem is, was and always will be Israel’s capital.

Apart from the fact that the city was the center of Jewish identity for three millennia, in the late 1940s and early 50s, modern Israelis set up the Knesset, Supreme Court, the President’s office and the prime minister’s residence there.

Yes, under just about any imaginable peace deal, Jerusalem will remain united and not divided again. The holy city will be shared and open to all and remain Israel’s capital.

Before the Six Day War, a critical mass of Arab leaders failed to accept Israel’s right to be a nation. Fifty years later, that remains a tragic truth.